Conventionally, there has been a motor-driven tool which is driven by a battery pack as a driving power, for the purpose of enhancing workability. This battery pack includes a housing formed with an opening, and a group of cells, a board, and a first terminal are contained in the housing. The terminal is provided near the opening so as to be engaged with a second terminal of a body part of the motor-driven tool or a charger. The board is disposed at a position remote from the terminal and connected to the terminal by a lead wire.